Success in Dorado-3 second test enhances field expectations

The Santos Ltd./Carnarvon Petroleum Ltd. joint venture has announced a successful conclusion to its 2019 drilling program at Dorado oil and gas field in the Bedout subbasin offshore Western Australia.

Santos, as operator, announced that the initial flow test from the main Caley reservoir in the Dorado-3 appraisal well has confirmed the main oil pool in the field is capable of producing flow rates at the high end of pre-drill expectations.

The initial clean-up flow test of the Caley sand achieved a maximum measured rate of 11,100 b/d of oil along with 21 MMcf/d of gas through a 68/64-in. choke. The test was conducted over a 12-hr period across an 11-m thick section 3,999-4,015 m from a total net reservoir interval of 53 m. Santos said this demonstrates the high quality of the Caley reservoir.

Santos said the flow rate is one of the highest ever from a North West Shelf appraisal well test. The results were achieved with only a 220 psi drawdown and, as with the test of the underlying secondary Baxter reservoir 2 weeks ago, the Caley flow rate was constrained by the capacity of the rig’s test equipment. This indicates the reservoir has capacity to flow at significantly higher rates.

Santos said the results are encouraging for development of the shallow water Dorado field and indicate the potential for flow rates of around 30,000 b/d from each production well in the Caley reservoir.

When added to the excellent rates in the Baxter reservoir, the joint venture is confident it can progress towards front-end engineering and design (FEED) entry in early 2020.

Dorado-3 was drilled to a total depth of 4,643 m by jack-up rig Noble Tom Prosser in 95 m of water depth about 900 m northwest of the Dorado-1 discovery made by Quadrant Energy Ltd. and Carnarvon Petroleum in July 2018. Santos announced a takeover of Quadrant in August 2018.

Dorado-3 is slightly down-dip from Dorado-1, but significantly up-dip from Dorado-2 drilled earlier this year about 2.2 km east of Dorado-1.

Once test operations are completed, Dorado-3 will be plugged and abandoned as planned. This will conclude the 2019 appraisal program.

Dorado and nearby Roc oil and gas fields are in WA-437-P about 160 km north northwest of Port Hedland on the Western Australian coast.

Santos has 80% interest, Carnarvon 20%.